A primary objective of this renewal proposal for research on the dynamics of speech articulation is to provide both descriptive and interpretative accounts of speech gestures and their neuromotor organization. Secondary objectives are (a) to study specific types of abnormal function and how they differ from normal speech, and (b) to develop the additional research techniques needed for the proposed basic and clinical investigations. Continuing use will be made of electromyographic measures, in part because they reflect the neural commands to the articulators, and in part because exceptional facilities have been developed for such work. Supplemental studies are planned of the changing configurations of the vocal tract during speech, employing direct, endoscopic, and X-ray movies. The simultaneous use of EMG and "viewing" techniques will aid in relating muscle activity to articulator movement and in determining how speech gestures are organized. Comparisons of direct measures of speech (EMG, X-ray, and acoustic spectrum) with corresponding measures derived from computer-based models of the speech process are planned (in connection with other research programs).